Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the heart using electrodes placed on the skin. These electrodes detect the small electrical changes that are a consequence of cardiac muscle depolarization followed by repolarization during each cardiac cycle (heartbeat). Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including cardiac rhythm disturbances (such as atrial fibrillation and ventricular tachycardia), inadequate coronary artery blood flow (such as myocardial ischemiaand myocardial infarction), and electrolyte disturbances (such as hypokalemia and hyperkalemia).
Advantages: one of the main ways to study the heart and diagnose diseases of the cardiovascular system.
ECG is indispensable in the diagnosis of arrhythmias and conduction, hypertrophy, coronary heart disease. This method makes it possible to speak with great accuracy about the localization of focal changes in the myocardium, their prevalence, depth and time of occurrence. ECG allows to reveal dystrophic and sclerotic processes in a myocardium, disturbances of the electrolyte metabolism arising under the influence of various toxic substances.
ECG is widely used for functional study of the cardiovascular system. The combination of electrocardiographic examination with functional tests helps to identify latent coronary insufficiency, transient arrhythmias, to make a differential diagnosis between functional and organic disorders of the heart.
- If you suspect a disease of the cardiovascular system, such as myocardial infarction;
- In case of deterioration of patients with heart disease;
- With discomfort and pain in the heart, chest;
- Episodes of loss of consciousness;
- At arrhythmic work of heart;
- Before any surgery;
- In diseases of internal organs, nervous system, skin diseases, etc. when the participation of the heart in the pathological process is suspected;
- High blood pressure;
- Noise in the heart;
- After SARS and Covid-19;
- The presence of diabetes or rheumatism, suffered a stroke.
No special training is required.
When performing an ECG, it is desirable to inform the doctor about taking drugs.
Immediately before the scheduled ECG recording, the patient should not eat, smoke, drink stimulants (tea, coffee, "energy"), exercise the body physically.
Lay the patient on the couch in a supine position. Degrease those areas of the skin where we will apply the electrodes - wipe them with a napkin soaked in saline (0.9%).
We impose electrodes: 4 - on the lower thirds of the inner surface of the legs and forearms, and on the chest - chest electrodes, equipped with suction pears.
To each electrode we connect wires of a certain color coming from the electrocardiograph.
Common labeling of electrocardiograph conductors:
- Red - right hand;
- Yellow - left hand;
- Green - left foot;
- Black - right leg (grounding the patient);
- White - chest electrode.
At registration of an ECG in 6 thoracic assignments in the presence of the six-channel electrocardiograph use the following marks of tips:
- Red - for connection to the electrode V1;
- Yellow - up to V2;
- Green - up to V3;
- Brown - up to V4;
- Black - up to V5;
- Blue or purple - up to V6.
Most often, the ECG is recorded in 12 leads:
- 3 standard (bipolar) leads (I, II, III);
- 3 reinforced unipolar leads;
- 6 chest leads.
An experienced cardiologist deciphers the cardiogram: assesses heart rhythm and heart rate. The result can be obtained on the same day or at the next visit to the doctor.
What the ECG shows:
- Heart rate. An ECG can help determine a too fast heart rate (tachycardia) or too slow (bradycardia).
- Heart rhythm. ECG may show arrhythmia (arrhythmia).
- Heart attacks. The ECG may show signs of current or past heart attacks.
- Insufficient blood supply to the heart. The ECG may show chest pain caused by decreased blood flow to the heart muscle, such as angina.
- Structural violations.
If you are concerned about chest pain or arrhythmic heartbeat, you should consult a doctor and perform an ECG.